Search results for "Multicellular organism"
showing 8 items of 58 documents
Cultural Heritage: Porifera (Sponges), A Taxon Successfully Progressing Paleontology, Biology, Biochemistry, Biotechnology and Biomedicine
2004
In 1876, Campbell (Campbell, 1876 [p. 446]) wrote “those beautiful ‘glass-rope sponges’, Hyalonema etc., have been found by our researchers to be ‘the most characteristic inhabitants of the great depths all over the world, and with them ordinary siliceous sponges, some of which rival Hyalospongiae in beauty’ “. The admiration for the beauty of sponges is documented since Aristotle (cited in Camus 1783), however the nature of these organisms and their phylogenetic position remained enigmatic until less than 10 years ago. E.g., in 1988 Loomis (Loomis, 1988 [p. 186]) wrote “the sponge cells are unspecialized flagellates held together by a glycoprotein extracellular matrix... they are multicell…
Morphology changes induced by intercellular gap junction blocking: A reaction-diffusion mechanism.
2021
Complex anatomical form is regulated in part by endogenous physiological communication between cells; however, the dynamics by which gap junctional (GJ) states across tissues regulate morphology are still poorly understood. We employed a biophysical modeling approach combining different signaling molecules (morphogens) to qualitatively describe the anteroposterior and lateral morphology changes in model multicellular systems due to intercellular GJ blockade. The model is based on two assumptions for blocking-induced patterning: (i) the local concentrations of two small antagonistic morphogens diffusing through the GJs along the axial direction, together with that of an independent, uncouple…
Multicellular tumor spheroids: an underestimated tool is catching up again.
2009
The present article highlights the rationale, potential and flexibility of tumor spheroid mono- and cocultures for implementation into state of the art anti-cancer therapy test platforms. Unlike classical monolayer-based models, spheroids strikingly mirror the 3D cellular context and therapeutically relevant pathophysiological gradients of in vivo tumors. Some concepts for standardization and automation of spheroid culturing, monitoring and analysis are discussed, and the challenges to define the most convenient analytical endpoints for therapy testing are outlined. The potential of spheroids to contribute to either the elimination of poor drug candidates at the pre-animal and pre-clinical …
Sponge proteins are more similar to those of Homo sapiens than to Caenorhabditis elegans
2000
We compared 42 phylogenetically conserved proteins from four marine sponges [Porifera] with almost the complete set of Caenorhabditis elegans proteins and all known proteins from humans. The majority of the sponge proteins are significantly more similar to human than to C. elegans orthologues/homologues. This finding reflects the accelerated evolutionary rate in the C. elegans lineage, since sponges split off first from the common ancestor of all multicellular animals. Furthermore, three sponge/human proteins were not found in C. elegans: (2–5)A synthetase, DNA repair helicase and lens βγ -crystallin. Sponges are the source of the most ancient proteins already present in the common ancestor…
Development, Differentiation, and Diversity of Innate Lymphoid Cells
2014
Recent years have witnessed the discovery of an unprecedented complexity in innate lymphocyte lineages, now collectively referred to as innate lymphoid cells (ILCs). ILCs are preferentially located at barrier surfaces and are important for protection against pathogens and for the maintenance of organ homeostasis. Inappropriate activation of ILCs has been linked to the pathogenesis of inflammatory and autoimmune disorders. Recent evidence suggests that ILCs can be grouped into two separate lineages, cytotoxic ILCs represented by conventional natural killer (cNK) cells and cytokine-producing helper-like ILCs (i.e., ILC1s, ILC2s, ILC3s). We will focus here on current work in humans and mice th…
Temperature-dependence of spontaneous mutation rates
2020
Mutation is the source of genetic variation and the fundament of evolution. At the interphase of ecology and evolution, temperature has long been suggested to have a direct impact on realised spontaneous mutation rates. The question is whether mutation rates can be a species-specific constant under variable environmental conditions, such as variation of the ambient temperature. By combining mutation accumulation with whole genome sequencing in a multicellular organism, we provide empirical support to reject this null hypothesis. Instead mutation rates depend on temperature in a U-shaped manner with increasing rates towards both temperature extremes. This relation has important implications …
[1] Neoglycoproteins from synthetic glycopeptides
1994
Publisher Summary Saccharide side chains of glycoproteins influence the physicochemical properties of the biomacromolecules and their stability against proteolytic degradation. Saccharide side chains of glycoproteins also play important roles as ligands in biological recognition and in the organized distribution of these compounds within multicellular organisms. Carbohydrate-lectin interactions are important, for example, in viral infections and for the recruitment and invasion of leukocytes into injured tissues. Although in a number of processes carbohydrates were revealed to be decisive recognition labels, in other biological selections peptide sequences proved to be the recognized areas.…
Biosilica
2012
Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO(2)), has become an exciting source of inspiration for the development of novel bionic approaches following 'nature as model'. Siliceous sponges are unique among silica-forming organisms in their ability to catalyze silica formation using a specific enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated 'biosilica' formation in marine demosponges, the involvement of further molecules in silica metabolism and their potential applications in nano-biotechnology and bio-medicine. While most forms of multicellular life have developed a calcium-based skel…